Ghrelin and growth hormone serum levels during the (original) (raw)
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HORMONES, 2011
ObjEctIvE: the exact role of ghrelin in the control of growth hormone (GH) secretion has not been completely clarified as yet. the aim of the present study was 1) to investigate the effect of a substance promoting GH secretion (clonidine) on ghrelin levels in children with short stature with growth hormone deficiency (GHD) and normal growth hormone (NGH), and 2) to assess possible correlations between GH and ghrelin values during the clonidine test. DEsIGN: Eighteen prepubertal children with short stature were included in the study. Using the results of two GH-provocative tests (glucagon and clonidine), the participants were divided into two groups: GHD and NGH. In both groups, ghrelin levels were determined during the clonidine stimulation test. rEsULts: Different responses regarding ghrelin levels during the clonidine stimulation test were observed in the two study groups (GHD and NGH). A decrease in ghrelin levels was observed in the NGH children accompanied by a rise in the circulating GH levels, whereas the GHD children demonstrated a rise in both ghrelin and GH levels. cONcLUsIONs: the data indicate an inverse relationship between circulating ghrelin and GH in NGH children, suggesting the presence of a negative feedback loop between ghrelin and GH. Analogous changes were not observed in GHD children.
Ghrelin concentrations in healthy children and adolescents
Clinical Endocrinology, 2003
OBJECTIVE In addition to its regulation by GH releasing hormone (GHRH) and somatostatin, release of GH from the pituitary is modulated by a third factor, ghrelin, which is expressed in high concentration in the stomach and is present in the circulation. Ghrelin has also been shown to cause weight gain by increasing food intake and decreasing fat utilization. Ghrelin is a potential candidate hormone to influence nutrient intake and growth. Its role through normal childhood and adolescence has not been fully defined. DESIGN Cross-sectional study in 121 healthy children (65 male, 56 female) aged 5 -18 years, in whom height, weight, body mass index (BMI), pubertal status and measurements of IGF-I, IGFBP-3, IGFBP-1 and leptin were available. METHODS Serum ghrelin concentrations have been measured in radioimmunoassay (RIA; Phoenix, AZ, USA) that detects active and inactive human ghrelin. Relationships between ghrelin and anthropometric data and growth factors were assessed by correlation and regression analyses. RESULTS Ghrelin was detected in all samples, with a median concentration of 162 pg / ml, range 60 -493 pg / ml. Prepubertal children had higher ghrelin concentrations than those in puberty [218 pg / ml ( n = 42) and 157 pg / ml ( n = 79), P < 0·001], with significant negative correlations between ghrelin and age ( r s = − − − − 0·39, P < 0·001) and pubertal stage ( r s = − − − − 0·42, P < 0·001). The decrease in ghrelin with advancing pubertal stage/age was more marked in boys than girls. In the whole group, ghrelin was negatively correlated to BMI SD ( r s = − − − − 0·24, P = 0·006) and to weight SD ( r s = − − − − 0·24, P = 0·008) but not height sds. Ghrelin was also negatively correlated to IGF-I ( r s = − − − − 0·48, P < 0·001), IGFBP-3 ( r s = − − − − 0·32, P < 0·001) and leptin ( r s = − − − − 0·22, P = 0·02) but not IGF-II. It was positively related to IGFBP-1 ( r s = + 0·46, P < 0·001). In stepwise multiple regression, 30% of the variability in ghrelin through childhood could be accounted for by log IGF-I (24%) and log IGFBP-1 (6%). CONCLUSIONS The fall in ghrelin over childhood and with puberty does not suggest that it is a direct growthpromoting hormone. However in view of the negative relationship with IGF-I and the positive relationship with IGFBP-1, this fall in ghrelin could facilitate growth acceleration over puberty.
Clinical Endocrinology, 2004
INTRODUCTION Ghrelin is the natural ligand of the growth hormone secretagogue receptor (GHS-R) and potently stimulates GH release in humans. Ghrelin is found in the hypothalamus, but most circulating ghrelin is derived from the stomach. Ghrelin stimulates food intake but circulating levels are low in obesity. We hypothesized that GH deficiency (GHD) might be associated with increased circulating ghrelin concentrations as a result of low GH levels. We therefore measured circulating ghrelin concentrations, leptin and body composition in subjects with GHD and healthy controls. METHODS Subjects with GHD (n = 18) were compared to healthy control subjects (n = 18), matched for body mass index (BMI). They underwent assessment of body composition [waist circumference, BMI and percentage body fat (using bioimpedance)]. Plasma ghrelin, leptin, insulin, GH and IGF-1 were measured in the fasting state. Plasma ghrelin was measured using a specific radioimmunassay, and the other hormones using commercially available assays. RESULTS The groups were well-matched for BMI (GHD vs. control; 32•9 ± ± ± ± 10•8 vs. 31•3 ± ± ± ± 11•7, P = ns) and waist circumference (GHD vs. control; 102•9 ± ± ± ± 20•0 vs. 99•8 ± ± ± ± 25•2, P = ns), but percentage body fat (GHD vs. control; 37•0 ± ± ± ± 9•1 vs. 29•4 ± ± ± ± 13•0, P = 0•06) tended to be higher in the GHD group. As expected, IGF-1 was lower in GHD (GHD vs. control; 12•5 ± ± ± ± 6•8 vs. 19•2 ± ± ± ± 5•8 nmol / l, P = 0•003). Ghrelin [GHD vs. controls; geometric mean (95% CI); 828•8 (95% CI 639•9-1074•2) vs. 487•9 (95% CI 297•2-800•2) pmol / l] and leptin [GHD vs. controls; 13•2 (95% CI 6•6-26•5) vs. 7•9 (95% CI 3•7-16•9) ng /ml] were similar in the two groups. Plasma ghrelin correlated inversely with waist circumference and waist hip ratio in GHD subjects (r = − − − − 0•6, P = 0•02) but not with IGF-1 or GH concentrations. There was no significant correlation in the control subjects. CONCLUSION Circulating ghrelin concentrations are influenced by body fat distribution, but not by levels of either GH or IGF-1. However, given that obesity is associated with reduced ghrelin concentrations and that GHD is commonly associated with increased body fat, it is possible that these two opposing influences on circulating ghrelin levels result in normal concentrations in subjects with GHD.
Ghrelin-induced growth hormone secretion in humans
European Journal of Endocrinology, 2000
Ghrelin is a novel growth hormone (GH) releaser acylated peptide that has recently been purified from stomach, and which potently binds to the GH secretagogue receptor. Ghrelin releases GH in vitro and in vivo in animal models, however its actions, potency and specificity in humans are unknown. In the present study, 12 healthy subjects were studied: 6 underwent four tests with ghrelin administered i.v. at the dose of 0 (placebo), 0.25, 0.5 and 1 microg/kg which corresponds to 0, 18, 37 and 75 microg total dose. A further 6 volunteers underwent two tests on different days with ghrelin at the dose of 3.3 or 6.6 microg/kg which corresponds to 250 microg and 500 microg total dose. Ghrelin-mediated GH secretion showed a dose-response curve, in which 1 microg/kg was the minimally effective dose in some individuals, but not as a group. On the contrary, the total doses of 250 microg and 500 microg elicited a powerful GH secretion, with a mean peak of 69.8+/-9.2 microg/l and 90.9+/-16.9 micr...
Effects of Growth Hormone (GH) on Ghrelin, Leptin, and Adiponectin in GH-Deficient Patients
The Journal of Clinical Endocrinology & Metabolism, 2003
Ghrelin is a recently discovered gastric peptide that increases appetite, glucose oxidation, and lipogenesis and stimulates the secretion of GH. In contrast to ghrelin, GH promotes lipolysis, glucose production, and insulin secretion. Both ghrelin and GH are suppressed by intake of nutrients, especially glucose. The role of GH in the regulation of ghrelin has not yet been established.
Effect of ghrelin on regulation of growth hormone release: A review
The occurrence of ghrelin indicates that GH release from the pituitary may be regulated not only by hypothalamic growth hormone releasing hormone (GHRH), but also by ghrelin, a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR). Objective: To review the role of ghrelin as a stimulant for the secretion of GH and GHRH. Methodology: We searched the following electronic databases: The Cochrane Library, MEDLINE, PubMed, Science Citation Index, BIOSIS, EMBASE, and CINAHL. The references of all identified studies were inspected for further randomized controlled trials. No language restrictions were applied. Results: The ghrelin receptor growth hormone secretagogue receptor-1 (GHSR-1) is found in several neuronal subtypes in the arcuate nucleus. In the presence of SS, the percent increase in GH released with human ghrelin plus GHRH was greater than that by either human ghrelin or GHRH alone. Conclusion: Ghrelin increases GH release and can be used as an adjunctive treatment. Reported adverse events were infrequent, mild, and transient. Future trials should report clinical as well as physiological outcomes. The role of ghrelin in the regulation of GH and its clinical implications needs further assessment.
The Journal of Pediatrics, 2004
Objective To establish mean plasma ghrelin levels during fetal life and childhood. Study design Cord blood was obtained at birth from premature (n = 29) and full-term newborns (n = 124). Fasting blood samples were taken from 224 normal subjects divided according to Tanner stage and sex. Ponderal index or body mass index was determined. Ghrelin; insulin-like growth factor (IGF)-I; IGF-II; IGF binding proteins 1, 2, and 3; insulin; glucose; and leptin levels were measured.